Synthesis of Phenol-Formaldehyde Resol Resins Using Modified Alkaline Lignin with Laccase

2011 ◽  
Vol 236-238 ◽  
pp. 1410-1414 ◽  
Author(s):  
Xiao Juan Jin ◽  
Wu Yu ◽  
Zhi Ming Yu
Keyword(s):  
Bonding Strength ◽  
Phenol Formaldehyde ◽  
Wood Adhesive ◽  
Methoxyl Group ◽  
Mediator System ◽  
Laccase Mediator System ◽  
Unmodified Sample

lignin (L)-based phenolic prepolymers with different phenol (P) substitution degrees were synthesized using the modified(M) L with laccase. It was found that the ML showed lower molecular value, polydispersity and higher reactivity compared to unmodified sample, and up to 30% of phenol can be substituted by MF to give LPF wood adhesive having better bonding strength in comparison to a control unmodified lignin phenol formaldehyde wood adhesive. MF was characterized using FTIR and GPC. FTIR showed that after the treatment of laccase, the methoxyl group increased, which was mainly due to the demethylation, and laccase/mediator system made the ether bonds of L cleave to produce more alcohol hydroxyl, as a result, the reactivity of ML was improved.

scholarly journals Efficient bleaching of non-wood high-quality paper pulp using laccase-mediator system

2004 ◽  
Vol 35 (2-3) ◽  
pp. 113-120 ◽  
Author(s):  
Susana Camarero ◽  
Olga Garcı́a ◽  
Teresa Vidal ◽  
José Colom ◽  
José C del Rı́o ◽  
...  
Keyword(s):  
Paper Pulp ◽  
High Quality ◽  
High Quality Paper ◽  
Mediator System ◽  
Laccase Mediator System

Sequential decolourization of reactive textile dyes by laccase mediator system

2009 ◽  
Vol 84 (3) ◽  
pp. 442-446 ◽  
Author(s):  
Ana P. M. Tavares ◽  
Raquel O. Cristóvão ◽  
José A. F. Gamelas ◽  
José M. Loureiro ◽  
Rui A. R. Boaventura ◽  
...  
Keyword(s):  
Textile Dyes ◽  
Mediator System ◽  
Laccase Mediator System

Fiber surface characterization of old newsprint pulp deinked by combining hemicellulase with laccase-mediator system

2011 ◽  
Vol 102 (11) ◽  
pp. 6536-6540 ◽  
Author(s):  
Q.H. Xu ◽  
Y.P. Wang ◽  
M.H. Qin ◽  
Y.J. Fu ◽  
Z.Q. Li ◽  
...  
Keyword(s):  
Surface Characterization ◽  
Fiber Surface ◽  
Mediator System ◽  
Laccase Mediator System

FTIR Analysis of the Lignin Structure Changes of APMP Treated by Laccase and Laccase / Mediator System

2013 ◽  
Vol 734-737 ◽  
pp. 2089-2093
Author(s):  
Fan Liu ◽  
Yu Liu ◽  
Jia Chuan Chen ◽  
Zhen Wang
Keyword(s):  
Oxidative Degradation ◽  
No Oxidation ◽  
Side Chain ◽  
Content Increase ◽  
Hydroxyl Content ◽  
Structure Changes ◽  
Mediator System ◽  
Chromophoric Group ◽  
Laccase Mediator System ◽  
Lignin Structure

In this Paper the Two-Stage Method of Enzyme-Mild Acidic Hydrolysis was Adopted to Separate Lignin from the APMP and the Modified Pulp Samples.And then Analyze the Lignin Structure Changes of the Modified APMP Lignin by Laccase and LMS(laccase/mediator System). it was Found that no Oxidation Took Place on Carbohydrates in the LMS, and Lignin Cα Hydroxyl Oxidization Produce α Carbonyl and H2O2 Bleaching can also Oxidation of Lignin, make the Conjugate C = α Increase;the Syringyl Structure Hydroxyl Content Increase, the Lignin Structure Macromolecular Side Chain Fracturing; Laccase and LMS Oxidative Degradation Chromophoric Group Unsaturated C = O, which can Improve the Brightness of Pulp and Create Better Conditions for Unbleached Pulp.

Preparation and Application of Modified Soybean Protein Adhesives

2010 ◽  
Vol 139-141 ◽  
pp. 706-709
Author(s):  
Zi Tao Sang ◽  
Shi Feng Zhang ◽  
Qiang Gao ◽  
Jian Zhang Li
Keyword(s):  
Sodium Hydroxide ◽  
Bonding Strength ◽  
Phenol Formaldehyde ◽  
Soybean Protein ◽  
Ftir Spectra ◽  
Absorption Peak ◽  
Type I ◽  
Curing Process ◽  
Protein Adhesives

In this study, a sodium hydroxide modified soybean protein adhesive (NSP adhesive) was prepared and mixed with phenol-formaldehyde (PF) resin in a ratio of 7:3 to form a compound adhesive (NSPF adhesive), and three-layer plywoods were prepared using the NSP adhesive and the NSPF adhesive. In order to understand the reactions between SP and PF resin during the curing process of NSPF adhesive, the SEM and FTIR spectra were employed to character the adhesives and the bonding strength of the plywoods was measured. The results showed that the bonding strength of the poplar plywood prepared with NSPF reached 1.00 MPa, and met type I plywood requirement in GB/T 17657-1999. There was new absorption peak appear at 1390 cm-1 in the FTIR spectra of NSPF adhesive, indicating that there were -NHCH2- structures generate in NSPF during the curing process in this research.

Preparation and Characterization of Silicate Wood Adhesive Modified with Ammonium Stearate

2014 ◽  
Vol 1033-1034 ◽  
pp. 1048-1053 ◽  
Author(s):  
Xin Li Zhang ◽  
Hong Hui Zhang ◽  
Yi Qiang Wu ◽  
Yun Chu Hu
Keyword(s):  
Bonding Strength ◽  
Water Resistance ◽  
Wood Adhesive ◽  
National Standard ◽  
Adhesion Properties ◽  
Good Thermal Stability ◽  
Thermo Gravimetric Analyzer ◽  
Infrared Spectrometer ◽  
Grade Ii

In order to improve the water resistance of silicate wood adhesive, a kind of silicate adhesive was prepared from water glass with silica as curing agent, and ammonium stearate as modifier. The chemical structure, surface morphology and thermal properties of the silicate adhesive were characterized by Fourier transform infrared spectrometer, scanning electron microscope, and thermo-gravimetric analyzer. As the two main measures of adhesion properties, the bonding strength and water resistance were also determined. The results showed that ammonium stearate was successfully introduced into the molecule structure of silicate, the silicate adhesive have good thermal stability in the range of 30~800 °C and the modified silicate adhesive had more smooth cured morphology. The bonding strength and 24h water absorption rate of poplar plywood glued by the silicate adhesive was 0.71 MPa and 22.81%, respectively, reaching the grade II of plywood performance's national standard.

Perfluorooctanesulfonate Degrades in a Laccase-Mediator System

2018 ◽  
Vol 52 (18) ◽  
pp. 10617-10626 ◽  
Author(s):  
Qi Luo ◽  
Xiufen Yan ◽  
Junhe Lu ◽  
Qingguo Huang
Keyword(s):  
Mediator System ◽  
Laccase Mediator System

scholarly journals Phenol-formaldehyde resins with suitable bonding strength synthesized from “less-reactive” hardwood lignin fractions

Holzforschung ◽  
2020 ◽  
Vol 74 (2) ◽  
pp. 175-183 ◽  
Author(s):  
Tainise V. Lourençon ◽  
Sami Alakurtti ◽  
Tommi Virtanen ◽  
Anna-Stiina Jääskeläinen ◽  
Tiina Liitiä ◽  
...  
Keyword(s):  
Theoretical Calculation ◽  
Bonding Strength ◽  
Phenol Formaldehyde ◽  
Chemical Reactivity ◽  
Lignin Valorization ◽  
Similar Performance ◽  
Press Time ◽  
Practical Implications ◽  
Resin Bonding ◽  
End Uses

AbstractThe substitution of phenol by lignin in phenol-formaldehyde (PF) resins is one of the most promising end uses of lignin valorization. Lignin from grasses and softwood has been the focus of the studies in this field as they present a higher number of theoretical reactive sites for resin synthesis. Herein we examined the composition and chemical reactivity of “less-reactive” hardwood lignin fractions and their performance in PF resins, synthesized by substituting 50 wt% of the phenol with lignin. Before resin synthesis, the samples were hydroxymethylated and the maximum formaldehyde consumption was recorded. By doing so, we observed that hardwood fractions consumed formaldehyde close to the theoretical calculation, whereas the reference softwood lignin consumed only about ¼ of the theoretical value. In the resin synthesis, we added formaldehyde to the formulation according to the measured maximum formaldehyde consumption. Thus, low values of free formaldehyde in lignin-PF (LPF) resins were achieved (<0.23%). Moreover, the resin bonding strength displayed similar performance irrespective of whether the LPF resins were made with softwood or hardwood lignin (range of 3.4–4.8 N mm−2 at 150°C and 45–480 s of press time). Furthermore, we concluded that hardwood kraft lignins present no disadvantage compared to softwood lignins in PF resin applications, which have significant practical implications.

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